Expanded CTG repeats trigger miRNA alterations in Drosophila that are conserved in myotonic dystrophy type 1 patients.

Autors de IIS La Fe

• Sheila Melisa Zuñiga Trejos

  Autor

• Manuel Mata Roig

  Autor

• Juan Jesús Vílchez Padilla

  Autor

• Ruben Dario Artero Allepuz

  Autor

Autors aliens a IIS La Fe

• Fernandez-Costa JM
• Garcia-Lopez A
• Fernandez-Pedrosa V
• Felipo-Benavent A
• Jaka O
• Aiastui A
• Hernandez-Torres F
• Aguado B
• Perez-Alonso M
• Lopez de Munain A

Grups d'Investigació

• Patología Neuromuscular y Ataxias

  

  Investigador Principal

  Teresa Sevilla Mantecón

Abstract

Myotonic dystrophy type 1 (DM1) is caused by the expansion of CTG repeats in the 3' untranslated region of the DMPK gene. Several missplicing events and transcriptional alterations have been described in DM1 patients. A large number of these defects have been reproduced in animal models expressing CTG repeats alone. Recent studies have also reported miRNA dysregulation in DM1 patients. In this work, a Drosophila model was used to investigate miRNA transcriptome alterations in the muscle, specifically triggered by CTG expansions. Twenty miRNAs were differentially expressed in CTG-expressing flies. Of these, 19 were down-regulated, whereas 1 was up-regulated. This trend was confirmed for those miRNAs conserved between Drosophila and humans (miR-1, miR-7 and miR-10) in muscle biopsies from DM1 patients. Consistently, at least seven target transcripts of these miRNAs were up-regulated in DM1 skeletal muscles. The mechanisms involved in dysregulation of miR-7 included a reduction of its primary precursor both in CTG-expressing flies and in DM1 patients. Additionally, a regulatory role for Muscleblind (Mbl) was also suggested for miR-1 and miR-7, as these miRNAs were down-regulated in flies where Mbl had been silenced. Finally, the physiological relevance of miRNA dysregulation was demonstrated for miR-10, since over-expression of this miRNA in Drosophila extended the lifespan of CTG-expressing flies. Taken together, our results contribute to our understanding of the origin and the role of miRNA alterations in DM1.